ADA bollard clearance requirements come from two sections of the U.S. Access Board's ADA Standards: Section 307 (protruding objects) and Section 403 (walking surfaces and accessible routes). The core rules: bollards along an accessible route must allow a 36-inch minimum clear width between posts, must not protrude into the path more than 4 inches if mounted higher than 27 inches above the floor, and must be detectable to a cane-using pedestrian. Compliance is mandatory for any commercial parking lot serving the public.
What Does ADA Section 307 Say About Bollard Clearance?
ADA Section 307 governs protruding objects in accessible routes. The rule structure has three parts: detectability, projection limit, and overhead clearance. Each part affects bollard specification.
Detectability Below 27 Inches
Any object lower than 27 inches above the finished floor or ground must be detectable by a cane sweep. A bollard is detectable because its base extends from grade -- a cane sweep at 18 to 24 inches will strike the post and alert the user. This is why ADA-route bollards almost universally extend to grade rather than mounting on a raised pedestal.
Projection Limit Above 27 Inches
Objects mounted between 27 and 80 inches above the floor are limited to a 4-inch projection into the accessible route. A typical 4-inch or 6-inch diameter bollard is itself a "wall-edge" object rather than a wall-mounted protrusion, so the 4-inch limit does not apply to the post itself; it applies to anything mounted to the side of the post (signs, lights, hardware) that protrudes laterally.
Overhead Clearance Above 80 Inches
Objects must allow 80 inches of overhead clearance along the accessible route. Bollard caps and decorative finials must not extend any horizontal element above the path between 27 and 80 inches if it would project more than 4 inches into the path.
What Does ADA Section 403 Say About Path Width?
ADA Section 403 governs walking surfaces and accessible routes. The headline number: a 36-inch minimum clear width must be maintained along the accessible route. Two adjacent bollards along the route must therefore be spaced at least 36 inches apart from face-to-face of post.
When the route passes between two bollards (a perpendicular crossing rather than a parallel boundary), the rule still holds: the gap between posts must be at least 36 inches. This is the same rule that governs spacing across bike-lane separation barriers and pedestrian-mall service-vehicle bollards.
The U.S. Access Board's interpretive guidance further notes that 60-inch passing space is required at intervals along the route to accommodate two-way wheelchair traffic. This affects bollard line-density: a continuous run of posts at 36-inch spacing can block two-way passage and the design should include 60-inch widening points every 200 feet at most.
How Tall Should an ADA-Compliant Bollard Be?
The standard parking-lot bollard height of 36 inches above grade satisfies ADA detectability requirements because it sits inside the visually detectable range above the 27-inch cane-sweep limit. See our bollard height standards guide for height-by-application detail. Three height-specific rules apply on accessible routes:
- Below 27 inches: Bollard must extend to grade (cane-detectable). Standard practice; no exception needed.
- 27 to 80 inches: Bollard body counts as the protruding object; lateral mountings (signs, hardware) limited to 4-inch projection.
- Above 80 inches: Overhead-clearance band; nothing in this band may project more than 4 inches if the route is a primary accessible path.
A 36-inch above-grade bollard with a 6-inch diameter contributes 6 inches to the total path obstruction at the bollard's location. Two such bollards on either side of a route consume 12 inches of the available width, which means the underlying paved surface must be at least 48 inches wide to deliver the required 36-inch clear gap.
Can a Bollard Block an Accessible Route?
A bollard placed within the 36-inch clear-width envelope of an accessible route violates ADA Section 403 and is a primary failure mode in compliance audits. The Cojo retrofit team has photographed multiple Oregon parking lots where well-intentioned post-incident bollard installations narrowed the accessible route below the 36-inch floor. Each one required relocation. The U.S. Department of Justice's ADA Title III enforcement actions include a documented history of penalty assessments where bollards encroach on accessible routes -- typical settlements run $20,000 to $80,000 plus attorney fees, well above the cost of moving the post.
For broader ADA compliance context see ADA parking requirements Oregon, which covers the parking-stall and access-aisle rules that operate alongside the accessible-route rules in this article.
What About Detectable Warnings at Bollard Bases?
Detectable warning surfaces (truncated dome panels) are required at the boundary between a pedestrian path and a vehicle area where the path cuts through a curb. Bollards do not require detectable warnings at their bases because the bollard itself is the detectable element. The only crossover case: when a row of bollards marks the boundary between a pedestrian path and a vehicle drive aisle, the underlying path may also need detectable warnings if it crosses a curb-cut at any point in the route. The U.S. Access Board's 2011 final guidelines on detectable warnings cover the curb-cut requirement; the bollard-line itself is separate.
How Does ADA Apply to Removable and Collapsible Bollards?
A removable or collapsible bollard creates a temporary 36-inch-plus opening when retracted but must satisfy the full Section 307 and Section 403 rules when extended. Two compliance rules apply:
- Extended state: The post must satisfy detectability, projection, and route width rules as if it were a permanent bollard.
- Retracted state: The remaining sleeve, baseplate, or below-grade socket must not introduce a tripping hazard. ADA Section 303 limits floor-level changes to 1/4 inch (vertical) or 1/2 inch (beveled) without a ramp. A retracted-bollard sleeve cap must sit flush within these tolerances.
The U.S. Access Board has issued specific guidance on retractable barrier compliance noting that removable post sleeves with caps are acceptable when the cap surface meets walking-surface flatness rules.
What Does Cojo Verify on ADA Bollard Installations?
Cojo's site walks include three ADA-specific verifications on every bollard install:
- Path width measurement: Tape-measured at three points along the accessible route between adjacent posts. Documented in the install record.
- Detectability check: Visual inspection that no bollard requires below-27-inch cane detection beyond the post's own grade-extending body.
- Projection check: Verification that signs, hardware, and decorative elements mounted to the post do not project more than 4 inches between 27 and 80 inches above grade.
The U.S. Department of Justice's 2010 ADA Standards for Accessible Design (the regulatory document at the federal level, published at ada.gov) sit on the Cojo office reference shelf and are consulted at every ADA-route project.
Where Has Cojo Designed Around ADA Clearance?
In April 2026 Cojo specified eight bollards along a Eugene retail-corridor accessible route. The original drawing called for 36-inch on-center spacing, which Cojo's site walk flagged as too tight: 6-inch posts at 36-inch on-center deliver only 30 inches of clear gap, which fails ADA Section 403. The corrected spec moved to 42-inch on-center, delivering a 36-inch clear gap and meeting Section 403 with no margin. The architect approved the revision in 4 hours. The lesson: ADA path-width math counts the post diameter against the available width, and "36-inch spacing" without a clarifying note can result in non-compliant installation.
Get an ADA-Compliant Bollard Quote
ADA-compliant bollard specification combines path-width math, detectability rules, and projection limits. Cojo's site walks deliver compliant specs on the first pass and document the clearance verification for the property manager's compliance file. Get a custom quote.